Yesterday we installed the battery rack under the bus.
It was a very tight fit. The rack sits right behind the drivers front tire. The batteries will be strapped down as a precaution and I may still install a sway brace even though it is quite sturdy.
Here it is underneath the rack:
This is it looking at the top. The metal box on the left is the stock battery housing:
These are the tops of the batteries:
Here is where the wires come down from the passengers side of the bus. The Red wire goes to the battery terminal:
The black wire is bolted to the frame: